1. Field of the Invention
The present invention relates to a data generating device, a data generating method and a data generating program and, particularly, to a data generating device, a data generating method and a data generating program for generating numerical data for controlling the operation of a cutting tool that machines a workpiece.
2. Background
NC (Numerically Controlled) machines in which the operation of a cutting tool is controlled by numerical control (NC) data are generally used for machining articles such as molds for injection molding by cutting a workpiece. When such a machine is used, it is necessary to generate NC data for the NC machine, i.e., data for determining the NC path (path of the cutting tool) from geometric (shape) data of the article to be machined. Conventionally, such NC data have been generated using an interactive operation system in which a skilled operator generates NC data while visually confirming the shape of the article to be machined. That is, the skilled operator generates NC data choosing the NC path considered to be most suitable for the shape of the article to be machined.
Since the shapes of articles to be machined have become complex due to diversification of consumer demands and progress in cutting technology, generation of NC data has come to require highly advanced techniques. The practice has therefore become to generate the NC data by automatic calculation using a large scale computer and to conduct the cutting of the workpiece by operating a high speed NC machine based on the thus-generated NC data.
However, since the shape of articles to be machined has become complex, the amount of NC data that needs to be generated has become huge, and, therefore, the time required for generating NC data has become longer than the time needed for the machining operation in the NC machine. In the series of processes from the generation of the NC data through the machining operation, therefore, it frequently happens that even though the high-speed NC machine has finished the cutting operation of one article, it cannot start the cutting operation for the next article because generation of the NC data for next article to be machined has not yet been completed. Thus the NC machine stands idle for some period of time and the operating efficiency is degraded.
With the life-cycle of commodities now shorter than ever before, there is a pressing need to reduce the period between the development and marketing of new commodities. This makes it necessary to promptly machine the injection molds and other articles needed to produce a new product. Owing to the fact that generation of the NC data is time consuming, however, machining of an injection mold often cannot be promptly started even though the design of the mold has been completed. Marketing of the new product is therefore delayed.
One object of the present invention is to overcome the foregoing problems by providing a data generating device, a data generating method and a data generating program that can generate numerical data for controlling the operation of a cutting tool in short time.
The present invention provides a data generating device for generating numerical control data for controlling the operation of a cutting tool when machining an article. The data generating device comprises geometric data input means to which a set of geometric data representing a shape of said article to be machined is input, partial geometric data generating means for dividing the set of geometric data into a plurality of sets of partial geometric data each representing one of a plurality of article parts constituting said article to be machined, a plurality of partial numerical control data generating means for generating from said sets of partial geometric data sets of partial numerical control data for machining article parts represented by the partial geometric data, and numerical data unifying means for generating a set of numerical control data for machining the whole of said article to be machined by unifying the plurality of sets of said partial numerical control data.
The so-configured data generating device can promptly generate the numerical control data because the generation of the numerical control data is decentralized and conducted separately for each part of the article to be machined.
In a preferred embodiment of the present invention, said plurality of partial numerical control data generating means generate at least two sets of partial numerical control data in parallel. The so-configured data generating device can promptly generate the numerical control data because the generation of the numerical control data is conducted in parallel.
In a preferred embodiment of the present invention, each of said article parts is formed as a layer extending in a direction perpendicular to a cutting depth direction of said cutting tool.
Due to such configuration, the cutting tool for machining article parts needs only to be moved in a direction perpendicular to the cutting depth direction in each layer and, therefore, the numerical data for machining each article part may be made uniform.
In another preferred embodiment of the present invention, all of said layers have the same thickness. According to this configuration, the control of the device can be simplified.
In another preferred embodiment of the present invention, the thickness of said layer is integer times said cutting depth of the cutting tool. According to this configuration, efficient and precise cutting can be achieved.
In another preferred embodiment of the present invention, the thickness of the layer is varied depending on the amount of the data for said layer. According to this configuration, the load of the calculation for generating the partial geometric data can be varied depending on the amount of data to be calculated.
In another preferred embodiment of the present invention, the thickness of a layer having a larger amount of said partial geometric data is set thinner than thickness of a layer having a smaller amount of said partial geometric data. According to this configuration, the load of the calculation in generation of the partial geometric data can be made uniform among the article parts.
In another preferred embodiment of the present invention, said partial numerical control data generating means comprises a plurality of computers.
In another preferred embodiment of the present invention, some of said computers are connected via network. According to this configuration, data are promptly sent and received.
Another preferred embodiment of the present invention further comprises NC data checking means for simulating the operation of said cutting tool based on the numerical control data generated by said numerical data unifying means.
Another preferred embodiment of the present further comprises data fractionating means for fractionating said sets of partial geometric data into smaller sets of geometric data representing smaller parts that can be machined in one cutting operation by said cutting tool.
In another preferred embodiment of the present, said set of geometric data is solid data.
In another aspect, the present invention provides a data generating method for generating numerical control data for controlling the operation of a cutting tool when machining an article to be machined. The data generating method comprises steps of inputting a set of geometric data representing a shape of said article to be machined, dividing said set of geometric data to generate a plurality of sets of partial geometric data each representing one of a plurality of article parts constituting said article to be machined, generating from said sets of partial geometric data sets of partial numerical control data for machining article parts represented by the partial geometric data, and unifying the plurality of sets of said partial numerical control data to generate a set of numerical control data for machining the whole of said article to be machined.
In another preferred embodiment of the present, said step of generating sets of partial numerical control data includes a step of generating at least two sets of partial numerical control data in parallel.
In another preferred embodiment of the present, said article part is set smaller in a portion where the amount of said partial geometric is large than in a portion where the amount of said partial geometric data is small.
In another preferred embodiment of the present, the method further comprises a step of NC data checking for simulating the operation of said cutting tool based on the numerical control data generated by said numerical data unifying means.
In another preferred embodiment of the present, the method further comprises a step of fractionating for fractionating said sets of partial geometric data into smaller sets of geometric data representing smaller parts that can be machined in one cutting operation by said cutting tool.
In another aspect, the present invention provides a data generating program representing instructions executable by a computer. The program comprises instructions for inputting a set of geometric data representing a shape of an article to be machined, instructions for dividing said set of geometric data to generate a plurality of sets of partial geometric data each representing one of a plurality of article parts constituting said article to be machined, instructions for generating from said sets of partial geometric data sets of partial numerical control data for machining article parts represented by the partial geometric data, and instructions for unifying the plurality of sets of said partial numerical control data to generate a set of numerical control data for machining the whole of said article to be machined.
In another preferred embodiment of the present invention, in said instructions for generating partial numerical control data, said article part is set smaller in a portion where the amount of said partial geometric data is large than in a portion where the amount of said partial geometric data is small.